Voltage regulating apparatus and method and voltage regulator thereof

Abstract

A voltage regulating apparatus and method and voltage regulator thereof are presented. The apparatus includes a first regulator and a second regulator. The first regulator is used for receiving an input voltage and outputting a first voltage according to the input voltage. When the input voltage reaches a steady voltage value, the second regulator is turned on so as to receive the first voltage provided by the first regulator and output a second voltage according to the first voltage or the input voltage.

1 . A voltage-regulating method, comprising:
 receiving an input voltage by a first regulator, and outputting a first voltage according to the input voltage;   turning on a second regulator when the input voltage reaches a predetermined voltage value; and   outputting a second voltage by the second regulator according to at least one of the input voltage and the first voltage,   wherein a value of the first voltage is smaller than that of the second voltage.   
   
   
       2 . The method according to  claim 1 , wherein the first regulator comprises a first quiescent current, the second regulator comprises a second quiescent current, and the first quiescent current is smaller than the second quiescent current. 
   
   
       3 . The method according to  claim 1 , wherein the first regulator comprises a first drive current, the second regulator comprises a second drive current, and the first drive current is smaller than the second drive current. 
   
   
       4 . The method according to  claim 1 , wherein the first regulator is a linear regulator, and the second regulator is a switch regulator or a linear regulator. 
   
   
       5 . The method according to  claim 1 , wherein the predetermined voltage value is a steady voltage value. 
   
   
       6 . The method according to  claim 1 , wherein the value of the second voltage is smaller than the predetermined voltage value. 
   
   
       7 . The method according to  claim 1 , wherein the step of turning on the second regulator further comprises:
 turning on the second regulator in normal mode.   
   
   
       8 . The method according to  claim 1 , further comprising:
 turning off the second regulator in sleep mode.   
   
   
       9 . The method according to  claim 1 , further comprising:
 turning off the first regulator in normal mode.   
   
   
       10 . A voltage-regulating apparatus, having an output terminal, comprising:
 a first regulator, coupled to the output terminal, for receiving an input voltage and outputting a first voltage; and   a second regulator, coupled to the output terminal, for outputting a second voltage when the input voltage reaches a predetermined voltage value;   wherein the input voltage is increased from an initial voltage to a steady voltage, and the predetermined voltage value is between the initial voltage and the steady voltage, and the first voltage is output by the first regulator circuit to serve as the output voltage before the second voltage output by the second regulator circuit as the output voltage.   
   
   
       11 . The apparatus according to  claim 10 , wherein the first regulator has a first property, the second regulator has a second property, and the first property is different from the second property. 
   
   
       12 . The apparatus according to  claim 10 , wherein the first regulator comprises a first quiescent current, the second regulator comprises a second quiescent current, and the first quiescent current is smaller than the second quiescent current. 
   
   
       13 . The apparatus according to  claim 10 , wherein the first regulator comprises a first drive current, the second regulator comprises a second drive current, and the second drive current is larger than the first drive current. 
   
   
       14 . The apparatus according to  claim 10 , wherein the second regulator outputs the second voltage according to one of the first voltage and the input voltage. 
   
   
       15 . The apparatus according to  claim 10 , wherein the first regulator is a linear regulator, and the second regulator is a switch regulator or a linear regulator. 
   
   
       16 . The apparatus according to  claim 10 , wherein the predetermined voltage value is a steady voltage value. 
   
   
       17 . The apparatus according to  claim 10 , wherein a value of the first voltage is smaller than that of the second voltage. 
   
   
       18 . The apparatus according to  claim 10 , wherein the value of the second voltage is smaller than the predetermined voltage value. 
   
   
       19 . The apparatus according to  claim 10 , wherein at least the second regulator is turned on or the first regulator is turned off in a normal mode. 
   
   
       20 . The apparatus according to  claim 10 , wherein the second regulator is turned off in a sleep mode.